I haven't read all of the replies. I used to think it was selfish and an awful thing to "do" to those who loved you. Now I realise that those who attempt and commit suicide truly believe that they are doing the best thing for themselves and for the people they love. They feel that everyone will be better off without them.
So, no, I don't think it's selfish or weak, just incredibly tragic.
Someone I knew killed herself recently, leaving behind her two young children. It breaks my heart that she was in such a dark place that even the overwhelming love she felt for her children couldn't take away her pain.